Abstract
Material extrusion (MEX) additive manufacturing (AM) is transforming the design and production of complex structures, providing reliable on-demand components. However, the effect of thermal history on the resultant microstructure and damage tolerance of MEX-AM materials is not fully understood. This research investigates the critical role of interfacial thermal history, which is dependent on processing conditions, in determining the fracture and fatigue behaviors of semi-crystalline polymers, as exemplified by polyamide-6 (PA-6). Utilizing infrared thermography, the thermal history, and its dependence on nozzle temperature of extruded PA-6, was investigated. Quasi-static and cyclic tests of compact tension specimens were used to evaluate fracture and fatigue performance. The KIC in samples produced at a nozzle temperature of 260 °C were 201% and 18% higher than those fabricated at 240 °C and 280 °C, respectively. X-ray computed tomography showed thermal history significantly influences interfacial diffusion and void content, directly affecting performance. Optical microscopy and digital image correlation identified damage mechanisms and examined strain evolution around crack tips, revealing that interfacial thermal history governed crack tip plasticity, impacting the energy release rate. This study establishes a crucial process-structure–property-performance relationship and highlights the damage tolerance of MEX-AM polymers, showcasing their potential for advanced structural applications.
Recommended Citation
A. M. Lea et al., "Effect of Thermal History on the Fracture and Fatigue Behaviors of Semi-Crystalline Polymers Prepared Via Material Extrusion Additive Manufacturing," Materials and Design, vol. 254, article no. 114012, Elsevier, Jun 2025.
The definitive version is available at https://doi.org/10.1016/j.matdes.2025.114012
Department(s)
Mechanical and Aerospace Engineering
Publication Status
Open Access
Keywords and Phrases
Fatigue; Filament fused fabrication; Fracture; Material extrusion; Polymer diffusion; Thermal history
International Standard Serial Number (ISSN)
1873-4197; 0264-1275
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2025 Elsevier, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Jun 2025
Comments
Department of Mechanical Engineering, Stanford University, Grant None